Numerous heat exchanger apparatus have been proposed in the past. Common objectives are economy of manufacture, efficiency of heat transfer, safety and long service life. Various prior art patents disclose heat exchanger methods and apparatus for accomplishing the foregoing general objectives. For example, U.S. Pat. No. 3,080,916 to Collins discloses a heat exchanger with a continuous tube threaded back and forth through a plurality of fins. The tube has a plurality of straight sections forming tube rows with spacing between adjacent tube rows. A first row of tubing sections is offset from a second row to permit air to pass through the first row and contact the second row.
U.S. Pat. No. 4,738,225 to Juang discloses a fin and tube heat exchanger having a 4.times.4 block of spaced tubes threaded through a multitude of fins. Flow through the tubes is split and merged by a plurality of flow splitting and flow merging manifolds that bridge adjacent tubes at either end of the heat exchanger. As in U.S. Pat. No. 3,080,916, the tubes in adjacent rows are staggered. The fin plates have a plurality of fin arrays to promote air turbulence to enhance heat transfer.
U.S. Pat. No. 4,169,502 to Kluck teaches a tube and fin heat exchanger for use as an automobile radiator wherein the tubes are arranged on a sinusoidal, wave or zig zag line. This arrangement, according to the patent, exposes all tubes to the cooling air current. The fins are provided with tear holes which, in conjunction with tube passage collars, space adjacent fins one from another.
U.S. Pat. No. 5,660,230 to Obusu et al. discloses a fin and tube heat exchanger wherein the leading and trailing edges of the fins have a sinusoidal or trapezoidal wave shape, with the leading and trailing edges described as being contoured to conform with isotherms around the fluid flowing through the tubes. The patent suggests that this form of fin promotes economy of manufacture by avoiding material wastage. Each of the fins has a plurality of louvers aligned on the fin body along the isotherms.
Notwithstanding the existing fin and tube heat exchanger technology, it remains an object in the field to produce heat exchangers which are yet more efficient, safe, durable, economical to produce and such is the object of the present invention.